A play on the word "coattails" where one rides on the success of another's joke. Admiration or praise is shifted from the original joke teller to the joke sniper
who is riding on joketails.
Guy: So then I said, "Those aren't buoys!"
Joke Sniper: That's what she said!
Audience: *increased laughed*
Guy: Dude, quit riding my joketails.